At the front of every text book on ancient Egypt is the famous quote by Herodotus that “Egypt is the gift of the Nile.” His message is a simple one, but it bears a profound meaning that still holds true today, namely, that Water is Life. A civilization that loses access to, or the ability to control, fresh water is doomed to collapse in short order.

Our own country owes much to a natural abundance of fresh water. Underground aquifers like the Ogallala are used to irrigate multiple states, and the Great Lakes hold a fifth of the world’s fresh water. Massive rivers like the Mississippi and the Colorado snake across the country, bringing life wherever they touch.

Yet even now, water scarcity and failures in our water infrastructure systems are all over the news. There’s the Western drought, the overdrafting of our aquifers and the toxic chemicals that are found in more water systems every day. We haven’t been investing enough in water infrastructure, and now that is putting public health at risk.

But new dangers spur new solutions, and people aren’t waiting for the glacial response of the government. Specifically, more and more people are getting interested in graywater reuse—taking gently used water from indoors and rerouting it to irrigate their landscapes. It’s a solution that’s custom-built for the Internet age: graywater systems are decentralized, eco-friendly and can be Wi-Fi enabled.

This is great news if you’re looking for a new way to grow your business, as graywater is very much on the ground floor right now. As watering restrictions tighten and regulatory restrictions loosen, there is now a system out there for any client, regardless of needs. Before you can get started though, there are some things you need to understand.

First, there are different types of wastewater. “Blackwater is, by definition, the household waste from kitchens and toilets,” said Bob Hitchner, chief sales and marketing officer for Nexus eWater, an Australian graywater company that is now entering the U.S. markets. Blackwater is strictly regulated, and must go directly to the sewer system—do not pass Go, do not collect $200.

Graywater, on the other hand, comes in two varieties, treated and untreated. “The plumbing code is very clear that untreated graywater should be used as soon as possible after it is collected,” said Hitchner. “The guideline is that graywater which has been allowed to stand for more than 24 hours cannot be reused.”

But with sufficient filtering and disinfection, treated graywater can be stored indefinitely for irrigation use. A year-long study, published last December by Ben-Gurion University of the Negev, Israel, found that using treated graywater for irrigation did not increase the incidence of gastroenteritis.

For a long time, plumbing codes equated blackwater and graywater, in practice if not in theory. Graywater was mixed with blackwater, and they were piped out of the house together. Fortunately, continuing regulatory advances in the Universal Plumbing Code (UPC) and the International Plumbing Code (IPC) are making it easier to install graywater systems with every new edition.

While state and municipal laws are getting more permissive, it’s still best to check out your local ordinances before jumping in. “If you are in the arid Southwest, in states like Arizona, New Mexico and Texas, it’ll be a lot easier,” said Laura Allen, cofounder of the graywater advocacy group Greywater Action.

Twenty states currently allow some form of legal graywater system, but living in one of these twenty doesn’t automatically mean you can set up shop. Many state and city regulators know next to nothing about graywater, and will err on the side of safety. That usually translates into requirements that each system be permitted, and rules that vary from city to city.

The end result is that the legality of offering graywater systems might come down to your local officials. “It depends on what city you live in, and who’s at the counter that day,” Allen said. “You could encounter very friendly and welcoming inspectors, or you could encounter extreme resistance and difficulty.”

Fortunately, the general ignorance of the subject cuts both ways. A local regulator that doesn’t know about against it. Educating them could be enough to get the rules changed.

After all, graywater is safe enough to be used on edible landscapes. “You can water edible plants as long as the graywater doesn’t touch the part you’re going to eat,” Allen said. If you can get graywater systems legalized in your area, you get to add a the perk of being first to market.

Of course, in order to offer graywater systems to property owners, you also need to know what systems are out there in the first place. Graywater systems can be divided into two categories: untreated systems that reuse the water as soon as it’s generated, and treated systems that graywater won’t be prejudiced new service to your business, with clean the water so it can be stored.

The gravity-flow system is the most intuitive of these options. “In a gravity-flow system, you are just putting a diversion in below the shower,” said Allen. “You have to have access to it in a crawl space or basement. Then if you have room, you can keep using larger ABS pipe and branch it out.”

Once the water from allowable sources has been diverted to a single outflow, it can be branched out to irrigate several mulch basins. This is where gravity-fed systems can get difficult. “You need to have it slope the whole way to whatever you’re watering,” said Lincoln Perino, owner of Ethos Rainwater Harvesting and Erosion Control in Tucson, Arizona.

On a small, flat lot, that may be easier said than done. “In that case, you’re adjusting the whole landscape to accommodate,” Perino said.

“You’re creating depressions in the soil, which not only hold the water, but give you a little more distance you can travel with the pipe.”

Depending on the layout of the building, your client’s graywater line may be coming out two feet underground, which poses problems for gravity systems. In these cases, “You really have to put in a pump system,” says Perino. “You bring your line out underground, and it feeds into a small barrel. Then in that barrel you have a submersible pump with a float switch on it. As soon as the graywater starts going into that barrel, it starts getting ejected by the pump.”

Depending on where you live, this is further complicated by an error in the 2012 edition of the IPC. According to Paul James, vice president of research and product development at Water ReNu LLC, Plano, Texas, it required that “the overflow from a water capture system must be connected back to the sewer by an indi- rect connection. An indirect connection means that the overflow has to reconnect to the sewer through a four-inch air gap.”

Although the rule was intended to prevent backflows, it inadvertently prohibited graywater systems. “In a new house being built on a flat lot, graywater is normally already 20 inches below ground,” James said. This means that, even if a graywater system can use a pump to make an indirect connection feasible, the system will be compromised if the sewer ever backs up. The 2015 IPC corrected this to allow for a backflow prevention valve to be used instead, but states which are using the 2012 version are still in error.

Even when the terrain won’t allow for a gravity-fed system, and the client is unwilling to pay for a pump, there’s a very simple graywater system that can be installed. In Laundry to Landscape, or L2L, systems, a washing machine sends its graywater to the landscape using its own pump. “It’s a system that I’ve been using a lot lately,” said Perino. “I really prefer it for the client’s ease of use, and for the overall cost.”

He also says there is an important rule of thumb to keep in mind with L2L systems, concerning the power limits of the washing machine’s pump.

“You get about a hundred feet of distribution. A little bit more than that if you have some slope, but you can’t push it very far,” Perino said. “So we tend to encourage people to get the destination for the water nearer to the source.”

An L2L installation starts with hooking the water discharge line of a washing machine up to a three-way valve. Then one leg is sent out to irrigate the landscape, and the last leg goes back to the sewer outflow to which the washing machine was originally connected. That last step is important, because if a washload contains soiled diapers, then the output is blackwater and that has to go into the sewer, not the landscape.

Blackwater isn’t the only concern, either. The soaps and detergents found in graywater usually contain valuable nutrients which are beneficial to plants, but some carry poison pills that must be avoided. “Products that contain boron, chlorine, or a lot of sodium shouldn’t go out to the landscape,” advised Allen.

The particulates in graywater also bar it from flowing through a regular irrigation system without filtering. The simplest answer is to distribute graywater through a separate drip system with robust tubing. “You pump it out through one-inch tubing with half-inch outlets,” Allen said. “It’s the skeleton of a drip system; there are no inline emitters, and no quarter-inch tubing.”

The other option is to filter out particulates, but Allen says that carries risks. “The biggest cause of system failure is installing a filter and then not cleaning it,” she said. “It will clog up because it’s designed to catch all the particles.” Fortunately, there are self-cleaning filters on the market, which periodically scour the filter with water or compressed air.

Filtered graywater can be run through a traditional drip irrigation system, but it still isn’t clean enough to be stored long-term. “Storing graywater, by code, is for a maximum of 24 hours,” James said, but he cautions that health codes aren’t the only reason to keep graywater moving. “If you store it until the end of the day, it creates a lot of issues with sludge and odor development,” he said. “That smell does come through the driplines.”

That is why James’ company, and a number of others like them, are focused on selling treated graywater systems to homebuilders. Their idea is that property owners want graywater systems as an appliance: a setand-forget system that conserves water and saves them money in the long term.

Getting a treated graywater system installed during the building’s construction lowers the initial costs, which make it a more attractive add-on. That’s not to say that landscape contractors are going to be left out in the cold, just that retrofitting graywater systems onto existing properties is a nascent industry.

When that industry really starts to get off the ground, contractors who already offer graywater installation services will be ideally positioned. James’ advice for those looking to learn retrofitting is to learn how graywater sources differ from property to property.

“When someone is working on their approach, the best thing is just to sit down and think for five minutes,” he said. “Where’s the water coming from? What’s the quality of the water? Is there a better location or source of water?”

If you’re retrofitting a hotel, the shower water might be too troublesome to use, but the hotel laundry is a very controlled environment. A residence with low-flow toilets might not have enough water to keep solids from backing up if you take all the other bathroom lines, so you might do well to leave the bathroom sink alone. Air conditioning condensate is another great source on many buildings, because it’s producing the most water when the weather is the hottest.

This kind of creative problem solving is right at the heart of graywater reuse. Water woes have awakened the public to the urgency of the situation, and waste will not be tolerated. As people open their eyes to the value of non-potable water, they will be looking for ways to unlock this hidden supply. What could be better for your business than offering them the key?